Summary of Work: The objective of this project is to develop a package of brief, safe and reliable measures of exercise tolerance that, in total, is broadly applicable and highly discriminating in population studies of older persons. The first phase of testing and evaluation has been completed at the Baltimore Veteran's Administration Medical Center through an interagency agreement (Y01-AG-4-0260). The following tests were administered on two occasions 7 to 10 days apart to a volunteer sample of 50 men and women age 54-80 years, 24 of whom had peripheral arterial disease: (1) timed usual and fast pace 4-meter walks; (2) timed usual and fast pace 20-meter walks; (3) 6-minute usual pace corridor walk; (4) seated step-test; and (5) treadmill walk. Heart rate at work, recovery heart rate, and blood pressure were measured. Two questionnaires were also piloted; one is a refinement of Taylor's Leisure Time Physical Activity questionnaire and the other measures physical function including ease of performance and level of fatigue as well as difficulty in performing higher order functional tasks. Preliminary results on test-retest reliability and associations among the walking and seated step tests were presented at GSA, November 1995. Analyses of the reliability and validity of questionnaires and final analyses of the exercise tolerance measures are proceeding. The original scope of work was completed in March 1996, approximately $15,000 under budget. A second phase of testing commenced October 1996, to evaluate a modification of the 6-minure walk, the HEALTH ABC Long Distance Corridor Walk (LDCW), designed to extend the testing range and improve the reproducibility of self-paced walking tests. Key features of the LDCW are the 2-minute warm-up walk that also serves as a stepped-down test and the focus on distance (400m) instead of time (e.g., 6 minutes). Performance on the LDCW and 6-minute walk were compared. Twenty men and women age 70 to 79 did both tests with a 15-minute rest between, during which they were administered a revised version of the physical activity questionnaire used in phase one. Test order alternated between subjects. Walking speed was consistently greater for the 400m walk than the 6-minute walk for all subjects and ending heart rate for the 400m walk was equal to or greater than ending heart rate for the 6-minute walk. Findings suggest that a target distance encouraged greater effort independent of fitness or test order. The LDCW protocol is being used in HEALTH ABC. A poster presentation of the protocol and evalution findings has been accepted for presentation at the 50th Annual Scientific Meeting of the Gerontological Society of American to be held November 1997.